Radio device



B. H. MAGOON RADIO DEVICE March 27, 1934.

Filed Jan. 10, 1931 (I v' V Patented Mar. 27, 1934 UNETED STATES PATENTOFFECE RADIO DEVICE 2 Claims.

This invention relates to a radio device, the general object of theinvention being to provide means for eliminating static and otherelectrical interferences to a great extent and to control the radio waveand hold back foreign signals.

This invention also consists in certain other features of constructionand in the combination and arrangement of the several parts, to behereinaiter fully described, illustrated in the accompanying drawing andspecifically pointed out in the appended claims.

In describing the invention in detail, reference will be had to theaccompanying drawing which shows diagrammatically the invention appliedto a radio device.

In this drawing, the numeral 1 indicates a binding post to which theantenna wire 2 is connected, and the numeral 3 indicates a conductorleading from the post to the terminal 4 of a switch arm 5. This arm isadapted to be moved into contact with any one of the terminals 6, 7, 8and 9. The terminal 7 is connected by the conductors 10 to the radiodevice which is shown generally at A. Two sets of coils, shown at B and0, form part of the invention, each set comprising a pair of coils, thecoil 11 of each set being wound over the other coil 12 of the set, theends of the wire of each coil being capacitively coupled, as shown at13. The coil 12 of the set E is connected with the post 1 and the coil12 of set C is. connected with the conductor 10. Coil ll of the set B isconnected by the conductors 14 with the post or terminal 9 and the coil11 of the set C is connected by the conductors 15 with the terminal 8.

A blocking condenser 16 is connected with the conductors l4 and 15 and avariable resistance 17 is placed in a conductor 15 between the coil 11of the set C and the condenser.

This invention, through its inductive coupled coils, blocking condenserand variable resistance, will, eliminate a great amount of static andother electrical interferences, thus controlling the radio waves andholding back foreign signals.

When the switch arm is contacting the post 6, the radio waves will passthrough all working parts of the circuit and when switched to post 7,the antenna is connected directly to the radio set and when this isdone, the invention absorbs a large percentage of interference andstatic. When the arm is in contact with the post 8, the waves will passthrough the variable resistance and the output coil, the other coilabsorbing interference, and when the arm is in engagement with the post9, the blocking condenser is brought into the circuits. The coils shouldbe from one to three or more inches long and from one-fourth to one inchin diameter. They should be made as small as possible in order to keepthe size of the unit as small as possible. The coils are preferablywound with from twenty to seventy-five or more turns of double cottoncovered or silk covered wire, the size of wire dependin upon the size ofthe tubing used to make the same. The coil 12 of set E is first woundupon the tubing and the open or free end of the wire is brought back andcapacitively coupled to the other end of coil, as shown at 13. Then thecoil 11 of the same set is wound over the first coil and is composed ofthe same number of turns of wire of the same size and kind of wire asthe first coil with the open end of this second coil capacitivelycoupled to the other end of the coil. This completes the firstinductively coupled input coil. The set C or output coil is constructedin the same manner.

All the parts may be mounted upon a panel of mica, bakelite or the likeand when built in a radio device, should be properly shielded.

It is thought from the foregoing description that the advantages andnovel features of the invention will be readily apparent.

It is to be understood that changes may be made in the construction andin the combination and arrangement of the several parts, provided thatsuch changes fall Within the scope of the appended claims.

What I claim is:

1. In combination with the antenna and input terminal of a radioreceiver, two pairs of inductances, the inductances of the respectivepairs being inductively coupled, one terminal of one inductance of onepair being connected with the antenna and one terminal of one inductanceof the other pair being connected with the input terminal, the ends ofeach inductance of each-pair being capacitively connected, and oneterminal of the remaining inductance of one pair being connected througha blocking condenser and a variable resistance with one terminal of theremaining inductance of the other pair.

2. In combination with the antenna and input terminal of a radioreceiver, a pair of concentric inductances one of which has one terminalconnected with said antenna, a second pair of concentric inductances oneof which has one terminal connected with said input terminal of thereceiver, the remaining inductances of both pairs being connected witheach other through a blocking condenser and a variable resistancaeach ofsaid inductances being open and having its terminals capacitivelycoupled.

BENJAMIN H. MAGOON.

